Uridine diphosphate glucuronic acid

Abbreviations NADPH, b-nicotinamide adenine dinucleotide phosphate reduced from 5 -phosphosulfate UDPGA, uridine diphosphate-glucuronic acid. 

UDPG was the first of a whole new class of nucleotides, in which the uridine diphosphate group is attached to a monosaccharide. Two important members of the class are uridine diphosphate glucuronic acid, the intermediate in the synthesis of glucuronides and of many other compounds, and uridine diphosphate N-acetylglucosamine which is an intermediate in the synthesis of mucopolysaccharides. Uridine diphosphate muramic acid was isolated by Park (P2) from Staphylococcus aureus... 

Strominger, J. L., Kalckar, H. M., Axelrod, J., and Maxwell, E. S., Enzymatic oxidation of uridine diphosphate glucose to uridine diphosphate glucuronic acid. 

F5. Fevery, J., Leroy, P., Van De Vijver, M., and Heirwegh, K. P. M., Structures of bilirubin conjugates synthesized in vitro from bilirubin and uridine diphosphate glucuronic acid, uridine diphosphate glucose or uridine diphosphate xylose by preparations from rat liver. Biochem. J. 129, 635-644 (1972). 

Gl. Gainey, P. A., and Phelps, C. F., Uridine diphosphate glucuronic acid production and utilization in various tissues actively synthesizing glycosaminoglycans. Biochem. J. 128, 215-227 (1972). 

Z3. Zhivkov, V., Measurement of uridine diphosphate glucuronic acid concentration and synthesis in animal tissues. Biochem. J. 120, 505-508 (1970). 

UDPGA uridine diphosphate glucuronic acid glucuronic acid donor. 

It has now been established that in common with many other glu-curonides, bilirubin glucuronide can be synthesized in the adult rat, rabbit, mouse, and guinea pig liver by the enzymatic transfer of glucuronic acid from uridine diphosphate glucuronic acid to an acceptor substance, namely, bilirubin (Fig. 3) (B17, G5, L3, L5, S8). The transferring enzyme (glucuronyl transferase) has been shown by Schmid et al. 

U UDP UDPGA dUMP UdRP Uracil Uridine diphosphate Uridine diphosphate glucuronic acid Deoxyuridylate-5 -monophosphate Deoxyuridylic acid... 

Other enzymes associated with xenobiotic metabolism are also altered by dietary protein levels. Epoxide hydratase can hydrolyze various epoxides and appears to be important in decreasing their toxicity and carcinogenicity, although it is involved in the metabolic activation of certain carcinogens. Low dietary protein depresses epoxide hydratase activity in our dietary model (8). This may indicate both a decreased ability to detoxify epoxides and a decrease in metabolic activation of specific carcinogens, such as benzo(a)pyrene. Woodcock and Wood (19) have reported that dietary protein deficiency increases the activity of uridine diphosphate glucuronic acid (UDP6) transferase activity. This indicates that... 

Typical reactions catalyzed by UGT enzymes require the cofactor uridine diphosphate-glucuronic acid, UDPGA. However, the C-terminus of all UGT enzymes contains a membrane-spanning domain that anchors the enzyme in the endoplasmic reticulum, and the enzyme faces the lumen of the endoplasmic reticulum, where it is ideally placed to conjugate lipophilic xenobiotics and their metabolites generated by oxidation, reduction, or hydrolysis. The lumenal... 

Uridine diphosphate glucuronosyltransferase catalyzes the transfer of glucuronic acid from uridine diphosphate glucuronic acid (UDPGA) to various... 

Roberts, R.M., 1971, The formation of uridine diphosphate-glucuronic acid in plants. J. Biol. Chem. 246 4995-5002. 

Fig. 4 Formation of uridine diphosphate glucuronic acid (UDP-GA) and its conjugation with clofibric acid. Inversion takes place during conjugation, the a-D-glucuronic acid forming a P-D-glucuronide. At a more alkaline pH, such glu-curonides may undergo intramolecular rearrangement to forms resistant to enzymic hydrolysis by P-glucuronidase.

Note Abbreviations NADPH, [Lnicotinamide adenine dinucleotide phosphate reduced from NAD, [Lnicotinamide adenine dinucleotide FAD, flavin adenine dinucleotide PAPS, 3 -phosphoadenosine 5 -phosphosulfate UDPGA, uridine diphosphate-glucuronic acid. 

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